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Background: It has been hypothesized that antibiotic usage in early life could contribute to development of overweight in childhood. Studies have seen association between antibiotic usage and overweight in childhood. We aimed to investigate the relationship between antibiotic exposure in infancy and development of body mass index (BMI) and body composition. Methods: A prospective mother–child cohort study of 738 pregnant women and their 700 children, Copenhagen Prospective Studies on Asthma in Childhood2010 (COPSAC2010). Information on antibiotic exposure was collected by interviews. Height/length and weight measures were collected at age 1, 2, 3, 4, 5 and 6 years and body composition was determined by a dual-energy X-ray absorptiometry (DXA) scan at age 3.5 and 6 years. Findings: 306 (46%) of the 661 children were exposed to antibiotics before 1 year of age. There were no differences in BMI z-score development at age 1–6 years between children exposed to antibiotics compared to unexposed: z-score difference, –0.06 (95%CI: –0.17;0.06), p = 0.33, and no sex-differences (p-interaction = 0.48). Children exposed vs. not exposed to antibiotics had comparable fat percentage at 6 years of age: log(mean difference), 0.60% (95%CI: −0.212 to 1.41), p = 0.15. Interpretation: Children exposed to antibiotics had similar BMI, BMI z-score and body composition between 1 and 6 years of life compared to unexposed children. Our study does not support the hypothesis that antibiotic exposure in infancy leads to development of obesity in the first 6 years of life. Funding: The Lundbeck Foundation, The Ministry of Health, Danish Council for Strategic Research and The Capital Region Research Foundation. Keywords: Antibiotic, Childhood, BMI, Growth, DXA scan, Fat percentage

C8 methylation of the title purine nucleotides was achieved in near neutral aqueous solution by reaction with (13)C enriched [Co(NH(3))(5)(CH(3))](2+). This cation decomposes upon dissolution in water by release of a methyl radical. The latter was identified by electron spin resonance (ESR) spectroscopy as the PBN/(13)C(.-)H(3) adduct (PBN=phenyl-N-tert-butylnitrone). When the purine nucleotide was used in large excess, the efficiency of the trapping by the C8 atom was determined by integration of the (13)C NMR signals to be 20-25% for GMP and 15-20% for AMP, respectively, at 37 degrees C.

A new high-potential iron-sulfur protein (HiPIP) has been isolated and purified to homogeneity from the soluble fraction obtained from light-grown cells of the facultative photoheterotrophic bacterium Rhodoferax fermentans. The new protein was identified as a HiPIP by virtue of its molecular properties such as the molecular mass (M(r) = 8.7 kDa), the Fe/protein ratio (3.8 +/- 0.2), the reduction potential (Em,7 = +351 mV), the electronic spectrum of the reduced and the oxidized protein, and the EPR spectrum of the oxidized protein. These molecular properties lie in the range observed for HiPIPs from other sources and, in particular, the iron content is consistent with the presence of one [Fe4S4] cubane cluster per molecule. The isoelectric pH values of the two redox forms are consistent with a basic protein. Kinetic studies of HiPIP oxidation, performed by monitoring the absorbance changes induced upon light excitation of the photosynthetic reaction center, give direct evidence of the role of the HiPIP in the photosynthetic electron transfer chain of Rf. fermentans.